「様式３－B」

課題番号（Project number）７４Interactive analysis of arterial stent and artificial
hemodynamic reconstruction between CFD and animal
experiments［１］組織（Research group）
代表者（Principal Investigator (PI)）：Yi Qian（ Faculty of Medicine and Health Sciences
Macquarie University）
対応者（Host researcher at IDAC）：
Tomoyuki yambe（Institute of Development, Aging and Cancer,Tohoku University）
Yasuyuki Shiraishi（Institute of Development, Aging and Cancer,Tohoku University）（（注）以下，分担者全員を記載する。
）

研究費(Expenditure report of research funds)：
物件費 400000YEN［２］研究経過（Research setup）
Purpose: The process of designing new aorticstenting procedure is to be related to local bloodflow circulation as well as the biologicalevaluation. In this project, we examined the flow
distribution in the lesion of the aorta or arteries
by CFD analysis based on the animal
experimental
hemodynamic
examination.
Arterial wall stresses caused by the interaction of
the stent with the flow structure in the vicinity ofaneurysm lesion of arteries and possibly stressinduced stent strut structure might be two
important parameters for the optimal design forthe stents. The basic knowledge of theseparameters after stent deployment in the subjects
derived and modelled by arteries might giveinsights in the recognition of biomedical
parameters of the optimal control of stent

deployment and in the understanding of thefeasibility of these stent procedures in eachpatient.
Methods: In the project, we established a newcollaborative platform for the biomedical analysis
in between the animal or human hemodynamics
and the numerical investigations. The researchplan of the project was as follows:
Animal experimental procedures (at IDAC):
Aortic dissection reproduction indescending aorta using goats（IDAC, Yasuyuki
Shiraishi, Tomoyuki Yambe）
Stent delivery and deployment in thelesion of the aorta in the animal experiments aswell as in the mechanical circulatory modelsystems
Computational fluid dynamics processing (atMacquarie, partly in IDAC):
Numerical reproduction of false andtrue lumens in the goat’s dissected aorta
Blood velocity mapping in the vascularcavities
Shear stress distribution in the false
lumen and the flow recovery after the stent
deployment
Feasibility studies associated with theCFD results and clinical investigations for theelimination of risks related with the stenting
procedures and results integration for preclinicalrequirements using animal hemodynamics andCFD (Macquarie/IDAC)
For the feasibility of the animal data
and CFD analyses, we focused on the two specifictopics: a) computer simulation of virtual stent
deployment, and b) haemodynamic simulation for
cerebrovascular stent using the method ofmodelling the flow-diverting stent as a porousmedium.

In FY2016, we performed animal
experiments for the 3-D reconstruction of aortic
aneurysms in goats in IDAC. All the animal
experimental procedures were allowed by theInstitutional Animal Experimental Committee inTohoku University (2016-AcA-034).
For the discussion of the assessment and progressof the project, the meetings were set on:- 26th April, 2016
- 10th September, 2016
- 9th November, 2016
- 24th February, 2017
Project summary assembly has been conducted
on 4th May, 2017.
［３］成果（Research outcomes）（３－１）研究成果（Results）
1) Reproduction of the aortic aneurysms for theanalysis of stent deployment
A new aortic stent had been designed,
and its characteristics of deploying in the aorta
could be tested in the aortic dissected aneurysm
model using goats. Prior to the hemodynamic
tests of stents, we made an exfoliation in theaortic wall to separate lumens into true and false
ones. Consequently, we performed an installationand deployment test with the stents with aortic
aneurysms which could represent a flow
separation and vortex in the false lumen.
2) Computer simulation of virtual stent
deployment
Flow-diverting (FD) compaction is a
newly developed method to improve the wiredensity across the aneurysm neck, thereby
promoting the clotting inside the aneurysm withless flow entering the aneurysm dome.
Nonetheless, how much difference in theaneurysmal haemodynamics influenced by thealteration of FD stent compaction level remains
unclear. Therefore, we seek to obtain the changes
in aneurysmal haemodynamics when virtual FD
stents in difference device diameters deployed atvarious compaction levels. In this study, wevirtually deployed FD stents with three device
sizes, at four compaction level with each case into
two patient-specific aneurysms. With thesimulation results, we discussed haemodynamic
parameters like velocity, mass flow rate, energy

loss and flow pattern. We found significant
information about metal coverage rate inaneurysms with different morphology.
3)
Haemodynamic
Simulation
for
Cerebrovascular Stent using the Method ofModelling the Flow-Diverting Stent as a Porous
MediumUsingporous
mediumasa
computational model of the real flow diverting
stent geometry in computational fluid dynamics(CFD) improves the simulation efficiency.
Adjustment of simulated permeability level of theporous medium will result in various projected
flow resistance force, which impact flow dynamics
around and inside the aneurysm dome. Diversity
in patient-specific aneurysm geometry and flow
diverting stent property also contribute to thedifference in both the resistance force and theaneurysmal haemodynamics. However, few
studies have discussed the relationship between
the setting of permeability and theintra-aneurysmal haemodynamics. As a result,
we provided future porous-medium stent
simulations with information on the parametricsensitivities, by altering the permeability andinitial resistance factor of the porous mediummodel.
（３－２）波及効果と発展性など（Futureperspectives）
The joint research project in the
preclinical studies had started based on thecollaboration between the Faculty of Medicine,
Macquarie University, and the IDAC. The
academic exchange program between theinstitutes has been expanded to the program
between the universities. As for this research
project, the international cooperation for
quantitative analyses in preclinical research will
be implemented to support the newstandardization of surgical approaches on
establishing the common standards worldwide.
［４］成果資料（List of Papers）
Mingzi Zhang, et al. Which stent diameter andcompaction ratio would benefit the patient themost?, Proc. Medical Engineering & PreclinicalStudies, Vol.2, 8-9, Nov, 2016.